Adult growth hormone deficiency (AO-GHD) is associated with increased mortality due to a higher risk of cardiovascular complications. Oxidative stress (OS) diminishes antioxidant capacity, leading to endothelial dysfunction and promoting thrombotic and inflammatory mechanisms. This increases the risk of cardiovascular diseases and metabolic disorders. Imbalances in the synthesis or signaling of endothelin-1 (ET-1) and nitric oxide (NO) are linked to hypertension, atherosclerosis, and heart failure. Additionally, elevated levels of asymmetric dimethylarginine (ADMA), an inhibitor of nitric oxide synthase, contribute to vascular endothelial dysfunction, increased vascular tension, higher blood pressure, and the activation of pro-atherogenic mechanisms. This preliminary study aims to investigate the cardiovascular effects of recombinant human growth hormone (rhGH) therapy in AO-GHD. The findings of this research suggest a potential association between rhGH replacement therapy in AO-GHD patients and a reduction in cardiovascular risk through its impact on ET-1, NO, ADMA concentrations, and OS status markers. These results have the potential to inform the optimization of rhGH replacement therapy protocols, thereby exerting a broader influence on the cardiovascular well-being of individuals undergoing such interventions.